| Western Australia (2000–2013) | New South Wales (2002–2008) | ||||
---|---|---|---|---|---|---|
Aboriginal | Aboriginal | Non-Aboriginal | ||||
Characteristic | Twin N = 880 n (%) | Singleton N = 33,229 n (%) | Twin N = 794 n (%) | Singleton N = 31,524 n (%) | Twin N 18,338 n (%) | Singleton N = 582,355 n (%) |
Groups compared and statistical significance reported1 | A | A | B | B | C | C |
 |  |  | D |  | D |  |
Gestation at first antenatal visitbCD, 2 | ||||||
 13 weeks or less | 120 (49) | 3797 (45) | 508 (64) | 18,955 (60) | 13,894 (76) | 410,156 (70) |
 14 weeks or more | n.p. | 4551 (54) | 270 (34) | 11,545 (37) | 4244 (23) | 166,711 (29) |
 No visit (WA) / No visit or missing (NSW) | n.p. | 125 (1) | 16 (2) | 1024 (3) | 200 (1) | 5488 (1) |
Maternal health and pregnancy complications | ||||||
 Gestational diabetesCd | 48 (5) | 1724 (5) | 28 (4) | 1105 e(4) | 1095 (6)3 | 26,541 (5) |
 Pre-existing diabetesbCd | 8 (1) | 557 (2) | 12 (2) | 230 (1) | 142 (1) | 3315 (1) |
 Pre-eclampsia/eclampsia/gestational hypertensionABCd | 148 (17) | 2650 (8) | 69 (9) | 1618 (5) | 2087 (11)3 | 31,855 (5) |
 Pre-existing hypertensionC | 18 (2) | 415 (1) | 8 (1) | 286 (1) | 237 (1)3 | 5547 (1) |
 Threatened abortionA | 56 (6) | 1002 (3) | – | – | – | – |
 Antepartum haemorrhageA | 84 (10) | 1787 (5) | – | – | – | – |
 Threatened preterm labourA | 256 (29) | 3099 (9) | – | – | – | – |
 Preterm prelabour rupture of membranesA | 174 (20) | 1695 (5) | – | – | – | – |